Are dashboards dead? Kind of. Which I think makes them undead.
No, they're not dead: because people keep asking for them, and other people keep making them.
Yes, they're dead, because they rarely get used: most dashbaords are requested, made, published, and then never accessed again.
Users love the idea of dashboards: that they'll have control, and can get all kinds of insights. But most data are too complex to understand without analysis -- more than you cna do in an interactive dash. So to answer any serious question, you're back to ad-hoc reporting. Which is fine. Dashboards have their uses -- it's just far fewer uses than we sometimes imagine.